A validated reverse phase stability-indicating HPLC method for bortezomib in the presence of degradation products and its process-related impurities

Abstract

Degradation pathway of bortezomib was established as per ICH recommendations in terms of validated and stability indicating reverse phase liquid chromatographic method. Bortezomib was subjected to stress using conditions of acid, base, oxidation, thermal and photolysis. Significant degradation was observed in acid and base stress conditions. Ten impurities were studied and the major degradant was hydroxyamide impurity. The stress samples were assayed against a qualified reference standard and the mass balance is found close to 98.2%. Efficient chromatographic separation was achieved on a Zorbax Extend C18(100 x 4.6 mm, 1.8 μm) stationary phase with simple mobile phase combination In the developed LC method, the resolution between bortezomib and ten potential impurities such as Imp-A, Imp-B, Imp-C, Imp-D, Imp-E, Imp-F, Imp-G, bortezomib isomer, hydroxyamide and bortezomib ester) was found to be greater than 2.0. Regression analysis showed r value (correlation coefficient) of greater than 0.999 for bortezomib and ten potential impurities. This method was capable of detecting the impurities of bortezomib at a level of 0.02% with respect to test concentration of 2.0 mg/mL. The developed rapid LC method was validated with respect to specificity, linearity, range, accuracy, precision and robustness for impurities.